Refid

The refid is a 32-bit field that identifies the source of time for the data packet. The NTP data packet also includes some timestamps, various other pieces of information, and the stratum of the time source, or the number of layers between the server and its “ultimate” source of time.

The primary reason for this is because the refid is used to detect a timing loop, which means that if machines A and B are exchanging time and B decides that it will follow A, then A can use the refid to make sure it won’t decide to follow B. Think of it as a “self-deceit” filter.

Reference ID (refid): 32-bit code identifying the particular server or reference clock. The interpretation depends on the value in the stratum field. For packet stratum 0 (unspecified or invalid), this is a four-character ASCII [RFC1345] string, called the "kiss code", used for debugging and monitoring purposes.

The REFID string overrides the default identifier ordinarily assigned by the driver itself. Root Delay (rootdelay): Total round-trip delay to the reference clock, in NTP short format. Root Dispersion (rootdisp): Total dispersion to the reference clock, in NTP short format.